The fifth season of "Community" begins Thursday on NBC, with the return of creator and show runner Dan Harmon, absent from his own show — he was fired — in Season 4. Writer-producer Chris McKenna has also returned; the pair shares credit for the opening episode, "Repilot," which will be immediately followed by a second episode, "Introduction to Teaching."

Indeed, there may have been some thought in the upper reaches of NBC that the series could be tweaked to attract viewers who might have found forbidding its barbed mesh of meta-humor, pop-cultural references, parody and reality shifts. But Harmon was cashiered not for his work but his work habits. If there was tension in the writers' room or trouble with deadlines, the show as it aired remained excellent, and when it failed, it was not for lack of nerve.

Many continuing series, not just of TV shows, but books and comics and franchised films, do, of course, successfully outlive their creators' involvement. The fourth season, overseen by Moses Port and David Guarascio, of the under-appreciated culture-clash comedy "Aliens in America" was not without its pleasures. Indeed, compared with other NBC comedies — and with the similarly complected "30 Rock" having already left the air — it remained quite radical.

Still, there was a sense that last season amounted to a kind of impersonation: an approximation of a voice that could never be that voice, even with some of the same writers in the room. And for all the playing with form — as in the puppet-musical episode, "Intro to Felt Surrogacy" — it did seem that some sort of concessions were being made to conventional narrative and feeling.

Significantly, the present state of "Community" could not have been predicted from its own relatively conventional first episodes. Even Jeff Winger, played by Joel McHale, reportedly the leading agitator for Harmon's return, played a familiar type, the selfish cynic whom human contact will warm. (The series was based on Harmon's own similar experience.) The negative expression of this progress is offered by Jeff in the fifth-season premiere, referring to the group's four-year progress through Greendale Community College, and to the series itself: "We went in one end as real people and out the other end as mixed-up cartoons."

In truth, it may be more accurate to say they started out as cartoons — as collections of attributes, assertions and motivations, written and played but not yet lived — and have suffered a sea change into something real and strange. The mutable reality they inhabit may not look quite like the one we walk through, but what happens there is not just clever burble; it has a Cubist integrity.

The actors and their characters have grown together; their community is not a conceit now, but really a statement of fact. It was the cast's insistence, reportedly, that made it possible for Harmon to return; it is as if the show is complete again.

And yet Harmon's first new episode, rather a dark one, is about coming back to a place you thought you'd left. Jeff has failed at his attempt to be a "hero at law" — "I am the system," says a gigantic robot in his TV ad, "I consume humanity, there is no escape" — and returns to Greendale ("ranked America's No. 2 community college by greendalecommunitycollege.com") in order to steal a file that will help his old partner (Rob Corddry) sue the school.

"I see your value now," Abed (Danny Pudi) tells Jeff when he encounters him there, quoting something Jeff told him in the pilot (and pointing the reference out). "We could repilot. This could be like 'Scrubs' Season 9 — a revamp, a do-over." The show is its own metaphor.

Though Harmon has expressed a hope that the fifth season does well enough — that he does it well enough — to merit a sixth, it's not as if anyone involved with "Community" can expect it suddenly to become a hit. What matters is that it has held its own against, or within, the humanity-consuming system.

Its audience is small, by network-hit standards, but it is very engaged — a part of the community the title describes. We may be few, and weird, and marginal, but we are in this together.

'Community'

Where: NBC

When: 8 and 8:30 p.m. Thursday

Rating: TV-14-DL (may be unsuitable for children under the age of 14 with advisories for suggestive dialogue and coarse language)